1. Field of the Invention.
This invention relates to a modular distribution frame assembly for use as a telephone line variable cross-connect system and more particularly to an assembly structure which allows terminal blocks to be arranged on one side of the frame in a manner such the necessary interconnections there between may be accomplished within a localized area referred to hereinafter as a "subzone".
2. Description of the Prior Art.
Modular distribution frames are well known in the art. One such example is described in U.S. Pat. No. 4,002,856 entitled "Modular Distribution Frame Assembly which issued on Jan. 11, 1977 in the name of William S. Sedlacek at el and which is assigned to the same assignee as is the present invention. That patent will be referred to hereinafter as the '856 patent. In order that a better understanding of our invention be obtained and as our invention is in some respects similar to the modular frame assembly described in the '856 patent, FIG. 1 herein shows a perspective view of the prior art assembly described in that patent.
Referring now to FIG. 1, there is seen the modular distribution frame system of the '856 patent designated generally by reference numeral 10. The modular distribution frame system 10 includes a plurality of modular frame assemblies 12, 13 and 14 positioned vertically side by side in a row. While only three modular distribution frame assemblies are shown, it will be understood that any number of frames may be incorporated.
The modular frame assembly 12 has a base structure 16 for securing to a floor support 17. The floor support 17 is part of a central office exchange and the plurality of subscriber or trunk lines coming into the exchange are directed through a plurality of subterranean cables 18. The cables 18 are divided into groups 19, 20 and 21 which extend upwardly through the support floor 17 and into the frame structure of each of the modular distribution frames 12, 13 and 14, respectively. The incoming subscriber lines can be introduced from an overhead cable if desired. All of the modular frame assemblies are substantially identical in construction and, therefore, only the frame 12 will be described in detail. The modular frame assembly 12 includes a vertical frame 22 preferably formed of metallic angle iron, bar stock and channel stock, as desired. Preferably the components forming the frame are welded together and the sharp edges and welds are finished to provide smooth surfaces at all corners. This preferably is accomplished in an assembly line production at the place of manufacture rather than fabricating the support frame on the site where it is to be used. The upper end of the frame 22 is provided with a telescopic section 23 and is adjusted in the vertical direction to engage a suitable upper support, not shown in the drawing.
A plurality of vertically aligned horizontally spaced apart protector blocks 26L and 26R are secured to the far side of the frame while a plurality of vertically aligned horizontally spaced apart line terminal blocks 27L and 27R are secured to the near side of the frame. The protector blocks 26L and 26R have a multitude of protector elements 28 inserted into receptacles therein. The protector elements 28 on the two vertical arrays of protector blocks 26L and 26R are interconnected with appropriate contact positions of the line terminal blocks 27L forming the vertical array to the left of the main vertical open column 32 by means of interconnecting cables 29. The cables 29 preferably have at least one end thereof provided with a mulit-position connector 30 which mates with a matching connector 31. The other end of the connector cables 29 may be wired directly to line terminal block contact positions either by wire-wrap or quick-clip connect method, or other suitable means, or may be connected to multi-position connectors and mated with matching connectors which can be mounted on the back side of the line terminal blocks 27L (not shown). The matching connectors in turn have been interconnected with appropriate contact positions of the line terminal blocks 27L. In essence, all incoming conductor pairs wired through protector elements 28 are now "protected" and these "protected pairs" have now been transferred to contact positions on the line terminal blocks 27L forming the vertical array to the left of the main vertical open column 32.
In a similar fashion, except not wired through any protector elements 28, the central office distribution lines (cables) 41 are routed into the basic modular frame 12 at the top via overhead cable racks (not shown) and connected by means of multi-position connectors 30 and 31 or directly wired to appropriate contact positions on the line terminal blocks 27R forming the vertical array to the right of the main vertical open column 32.
It is within this main vertical open column area 32 that most of all subsequent jumper wire 36 used will be stored while providing the desired variable interconnection between appropriate "protected pairs" appearing at contact positions on the line terminal blocks 27L on the left and related central office distribution lines (cables) 41 appearing at contact positions on the line terminal blocks 27R on the right.
The main vertical open column 32 is formed by a plurality of spaced apart retainer rings 33. The retainer rings 33 have openings 34 formed by closely spaced apart terminating ends of the retainer rings so that jumper wires 36 can be easily inserted into the ring in a vertical fashion as seen in FIG. 1. The jumper wires 36 are connected to appropriate terminating pins of the line terminal blocks 27L and 27R of one distribution frame assembly and can be connected to another appropriate pin of another terminal block of another distribution frame assembly. Therefore, the jumper wires 36 may travel from one frame to another frame along an upper support or tray as indicated generally by reference number 38 or along a lower support or tray, as indicated generally by reference number 39. The base structure of each of the modular distribution frame assembly 12, 13 and 14 form wire run support trays on both sides thereof and designated generally by reference numerals 39 and 40. It will be seen in the system drawing of FIG. 1 that a plurality of input cables 41 extend fromthe upper end of each of the modular distribution frame assemblies and are directed in an overhead fashion from appropriate terminating ends at a central office equipment block.
The frame assembly of the '856 patent has the advantages of being modular, essentially assembled in the factory prior to installation and relatively easy to install at the central office. While that assembly has both an upper and lower jumper support or tray to allow jumper wires to travel from one frame to another frame, it has been found that under certain circumstances the upper and lower trays may become congested by having a large number of jumpers therein. It was then recognized that it would be desirable to provide in a single modular frame, means by which such jumper congestion could be avoided if desired while at the same time preserving all of the advantages present in the frame assembly of the '856 patent.